Solid-phase micro extraction (SPME) method and stir bar sorption extraction (SBSE) method have been suggested as sample extracting method for introducing a sample to an analyzer (GC, LC, etc.).
The both methods are sample extracting methods applying the principle of solvent extraction which use a liquid phase as a stationary phase and transfer of substance in accordance with partition coefficient. Therefore, when a rapid sample extraction at a high recovery ratio is to be performed, there are involved various factors such as kind and film thickness of the stationary phase, extraction temperature, salting-out, extraction time, sample amount, pH adjustment, influences by contaminating substances and stirring rate and these methods are disadvantageous in the practical use.
SPME is a concentration method which aims at allowing a liquid phase such as PDMS coated on a glass fiber, glass, etc. or an adsorbing material mixed with the liquid phase to retain solute components dissolved in a solution in accordance with phase equilibrium as disclosed in Japanese Patent No. 3081239.
In this method, the thus held solute components can be inserted into the injection port of GC just as they are and vaporized and desorbed inside the injection port of GC.
In the meantime, SBSE includes a method using a magnet-embedded glass piece coated with a liquid phase such as PDMS, which is put in a vial bottle. The glass piece has the function of performing stirring in the target sample as disclosed in Japanese Patent No. 3462443.
The methods mentioned above have spread as methods which enable to perform concentration analysis very inexpensively and readily, and as simple and convenient apparatus for concentration analysis of samples such as food, fragrance components, clean water VOC, atmosphere and pesticides.
The retention ratio of the sample in the solution by the SPME currently performed in accordance with phase equilibrium is generally from several % to around 30%. In order to improve the extraction of the substance in the sample solution (i.e., for increasing the partition coefficient) in SPME and SBSE, it is necessary to increase the adsorbed sample amount by increasing the volume of the stationary phase.
However, increase in the volume of the stationary phase leads to the increase in the thickness thereof, and as a result, it takes an extended time to reach the condition where the concentration of stationary phase and the concentration in the sample solution are in the equilibrium.
It also takes time to extract (desorb) the adsorbed target substance from the sample solution with heat or a solvent, and the peak of the chromatogram becomes broad.
Furthermore, there is a defective that the heat for an extended time causes decomposition of a target component. In addition, when the adsorbed amount of a target component is small, equilibrium collapses due to the existence of the matrix, which makes difficult to allow correct adsorption.
In addition, PDMS is applied only to the surface of the glass fiber or the glass and has small surface area. Therefore the amount of the liquid phase which can be held is restrictive, and the absolute recovery ratio is low.
On this account, an object of the present invention is to provide a monolith adsorbent which can adsorb a sample solution of an extremely small amount or in a low concentration readily in a short time, enables to extract the components held thereby with a small amount of solvent or heating for a short time, and enables to secure the sample necessary for the analysis extremely easily as well as an adsorption method and an apparatus using the same.
Another object of the present invention is to provide a monolith adsorbent material with better adsorption efficiency for thermal desorption and with better solvent extraction efficiency than those used in the conventional solid-phase extraction methods, and it enables downsizing.